Techniques for WCAG 2.0

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H28: Providing definitions for abbreviations by using the abbr and acronym elements



This technique relates to:

User Agent and Assistive Technology Support Notes

Most graphical user agents render text enclosed within an abbr or acronym element with a dotted line below or surrounding it. In addition, when the mouse hovers over the element, the expansion is displayed as a tool tip.

In Internet Explorer 6 and below, items marked using the abbr element are not displayed with any additional formatting nor does the expanded version display as a tooltip when the mouse hovers over the item. Future versions are expected to provide these features for the abbr element.

JAWS 6.2 and WindowEyes 5.0 support the abbr and acronym elements. They can all be set to speak the title attribute when these elements are encountered. Within a given product the abbr and acronym elements are rendered the same way.


The objective of this technique is to provide expansions or definitions for abbreviations by using the abbr and acronym elements.

It is always appropriate to use the abbr element for any abbreviation, including acronyms and initialisms. When using HTML and XHTML, initialisms and acronyms may be marked up using the acronym element. XHTML 2.0 proposes eliminating the acronym element in favor of the more general abbr element.


Example 1: Using abbr element to expand abbreviations.

Example Code:

<p>Sugar is commonly sold in 5 <abbr title="pound">lb.<abbr> bags.</p>
<p>Welcome to the <abbr title="World Wide Web">WWW</abbr>!</p>              

Example 2: Using abbr element to define abbreviations.

Example Code:

<p>Tasini <abbr title="and others">et al.</abbr> <abbr title="versus">v.</abbr>
The New York Times <abbr title="and others">et al.</abbr> is the landmark lawsuit 
brought by members of the National Writers Union against ......</p>  

Example 3: Using the acronym element to expand an acronym

Example Code:

 <p>The use of <acronym title="Keep It Simple Stupid">KISS</acronym> became popular in ...</p>        

Example 4: Using the acronym element to expand an initialism

Example Code:

 <p><acronym title="World Wide Web">WWW</acronym></p>


Resources are for information purposes only, no endorsement implied.



  1. Check that an expansion or definition is provided for each abbreviation via abbr or acronym.

Expected Results